The IDEAL 61-502 120V AC GFCI receptacle tester can be used to test if the electrical outlet is wired properly. It will indicate a correct wiring condition as well as the following wiring faults; open ground, reverse polarity, open hot, open neutral , hot and ground reversed, and hot on neutral with hot open. Simply plug it in the outlet and compare which lights are lit to the legend on the tester. It will also trip any GFCI's in circuit by pressing the black button. A test light will turn on, indicating the activation of the GFCI test and the GFCIs will trip if they are functioning properly.